Actuators are devices that exhibit a predictable motion, change in rigidity, force and/or moment in response to a particular input. One common type of fluid-driven actuator is a pneumatic cylinder, in which air pressure is typically used to extend or retract a solid rod along a tubular enclosure. Such actuators are characterized by a single degree of freedom (DOF) and components that slide relative to one another. Devices exhibiting multiple degrees of freedom of movement often require multiple single DOF actuators. Devices capable of motion along complex motion paths, such as multi-axis servo-driven robotic, can be very expensive and require complex programmable control systems. Modern robotics also require special considerations regarding safety in manufacturing environments where humans are also present.